Grinding element



United States Patent I72] inventors Leslie Palyi 23 Larabee Crescent,Dons Mills; Nicholas Pora, 98 Banmoor Blvd., Toronto, Ontario, Canada[21 Appl. No. 759,345 [22] Filed Sept. 12, 1968 [45] Patented Dec. 8,1970 541 oluNmNc ELEMENT 13 Claims, 9 Drawing Figs.

[52] US. Cl. 146/182; 24 l/260, 241/298 [51 Int. Cl. B02c 7/02 [50]Field otSearch 146/182, 192; 241/298, 296, 260, 92

[56] References Cited UNITED STATES PATENTS 804,738 11/1905 Kreps241/298 583,532 1/1897 Halin 2,409,453 10/1946 Stucketal,

ABSTRACT: This specification discloses a grinding disk or milling burrof the type used in rotary disk grinders and mills for grinding up grainand a wide variety of other material, said disk having a grindingsurface formed of a plurality of separate blade members spaced apart byspacer means which are replaceable for reconditioning of the grindingdisk by merely removing the blade members and spacer means from asupport member and replacing them with new blade members, and alsodiscloses such a grinding disk having a particular arrangement ofseparate blade members incorporating teeth of graded sizes on the edgeof the blade and being arranged together to form a grinding surface of aparticularly effective grinding action.

PATENTEDDEB 8|97U 3545.513

SHEET 1 UF'E FIG.4

' A- //////m) .1 I j INVENTORS LESLIE PALYI NICHOLAS PORA a Mm PATENTEDon: 8mm 3.545513 snm 2 OF 2 INVENTORS LESLIE PALYI NICHOLAS PORAGRINDINGELEMENT This invention relates to grinding and millingapparatusand -moreparticularly to a new and improved grinding disk ormill bur applicable toa wide variety of rotary disk grinders and mills.

Disk grinding and milling apparatus presently in: use usuallyincorporates complementary rotatable and nonrotatable'disk membersaxially displaced from one another within a housing whereinthe spacingbetween the disk members can be adjusted. The disk members presently inuse have large grinding grinding disk for use in the grindingapparatuswhich-provides v a pluralityof separateremovable blades with teeththereon separated by spacers or filler and arranged andsuppoited on abacking plate to establish a grinding face on each grinding i from.aslotted opening 19 forvarying the location of shaft 21.

member. The blades and spacers are arranged with channels formed betweenthe blades on each grindingysurface permitting free air circulation andhigher operating speeds with very little temperature rise in the bladesthrough friction, In addition, the teeth of each blade are progressivelyvaried with coarse teeth at the entrance to the grinding surface-andfine teeth at the outlet end of the grinding surface. Also thepgapbetween the grinding surfaces of the rotatableandnonrotatable'grindingmembers is progressively reduced from the;-entrance end to the grindingsurfaceto the outlet end of the grinding surface. This permits thematerial to be ground to easily enter the gap between the grindingsurfaces.

It is an object of this invention to provide a. grinding disk apparatusbuilt up of separable blademembers which are easily replaced.

It is a further object of this invention to provide adiskgrindingapparatus'having an annular blade arrangement built up ofseparable blades of arcuate shape.

It is another object of this invention to provide'afdisk grinding memberwhich produces little friction at thegrindingfaces thereof and dissipateheat readily.

The foregoing and otheradvantages. will become} apparent from thefollowing description of the preferredembodiment of nally threaded holes42 to receive a screw member 43 to lock the invention which is heregiven by way of an examplewith v reference to the following drawingsand'in whichlike reference devices refer to like parts thereof through thevarious views and diagrams, and in which:

FIG. 1 is a perspective view of a typical diskgrinder-partly cut awayembodying the features of the invention;

FIG. 2 is a plan view of a portion of the grindingdisk embodying thefeatures of the invention;

1 FIG. 3 is an enlarged perspective view of a segment of the disk ofFIG. 2 partly cutaway;

FIG. 4 is a sectional view along4-4 of'FIG. 1;

FIG. 5 is an enlarged perspective view of a blade and spacer accordingto the invention;

. FIG. 6 is a plan" view of a blade and spacer;

FIG. 7 is a schematic viewshowing a preferred arrangement of blades andspacers;

FIG. 8 is a plan view of an alternative embodiment; and

FIG. 9 is a section along'the line 9-'9 of FIG.I2,.greatly exaggerated.

The disk grinding anparatus is illustrated; in ,FlG.1 ,.and

generally indicated as 10, beinga typical grinder of-xwell- Lever.20 islocated at the bottom of hopper 16 for controlling the rate of flow offeed therefrom by conventional means (not shown). 1 V

Within the casing 11 is an electric motor M with an output shaft2l whichextends through the casing .11 and a free end 22 almost touches the wallof the casing 12. The free end'22 is threadedto receive thereon'amounting plate 23. A rotatable grinding'member 24 is connected on themounting plate 23 by bolts 25. A nonrotatable grinding member 26 isconnected on the. casing 11 by similar bolts (not shown). Connectedaxially around the output shaft 21 is an annular plate 27 having threeimpellers .28 extending outward from the plate 27 for distributing.ungroundfeed therearound, A central opening 29, through casing portion11 permits passage of feed from hopperl6.

. According to the i'nvention'the grinding members 24 and 26 .eachcomprise an annularring 30 with an axial opening 13 therethrough andspaced apart parallel side surfaces 32 and 33 xwith a machined-outrecess 34 in one side surface 32, as shown best in FIG. 3. The recess 34has a bottom wall 35 and two side walls 36 and 3 7.'The bottom wall 34is not parallel to the side surfaces 32 and 33 and is slanted. The sidewall 36 ex- :tends from the side surface 32 to the bottom wall 35. Theside awall-37 isformed with a channel 38 adjacent the bottom wall.Within' the recess 34 arepositioned on the bottom wall 35,alternategrinding blades. 39 and spacers 40 extending out of therecess:34 approximately normal to the side surfaces 32 and 33, asshown in FIG.2, filling the entire recess 34 around its fullextent. An. annularmember 41 is positioned in the recess34 and makes contact with the sidewall 36 to secure the blades 39 and the spacers 40 in position. Betweenthe annular ring130 and annular member 41 are a plurality ofintertheannular member 41 to the annular ring 30.

Each blade 39comprises the body portion 44, a bottom edge 45 and anupper edge 46 spaced apart therefrom, inner .andvouterends tland 48 jointhe bottom edge 45 to the top edge-46. Extending outward from each-end47 and 48 are -innerrand outer lugs49 and 50. On the top edge 46 of theblade 39 are .cut teeth 51, preferably of varying pitch, the

'teethf5lat the inner end being'of, for example, 4 pitch while 'width ofthe blade and the fine teeth cuttingmore or less in line with the blade.

Alternativelythe blades 39 may extend diagonally from the entrance endof the grinding member to the outlet end of the grinding member. Theblades 39 onthe rotatable grinding :member 24 and the nonrotatablegrinding member 26 oppose one another as shown in FIG. 2, so that wheninposition the blades 390i: the grinding member 24 cross the blades 39of the nonrotatable grinding member 26 at a large number ofpredeterminedintersections. The blades 39 crossing causes :t'he-materialtherein to be ground up.

The spacers 40 have a similar structure as the blade 39 with lugs 49 and50 except for the height of the body portion 44 which is lower and thereare no teeth therein. One or more 1 spacers340' are placed betweenadjacent blades 39 in one embodiment of the invention, to give airchannel between the blades 39. The numberof spacers 40 to be usedbetween the blade 39depend on the desired separation between the blades.39, two ormore spacers 40 providing a greater air space and henceimproved cooling. A filler material may be substituted be ground.

In operation, the electric motor is operated to rotate the shaft 21 andthe rotatable grinding member 24 attached thereto at the free end 22 ina clockwise manner. The nonrotatable grinding member 26 is fixed to thecasing 11 and does not rotate. The rod 18 is connected to a mechanism(not shown) which permits the operator to vary the gap distance betweenthe rotatable grinding member 24 and the nonrotatable grinding member 26such as by sliding shaft 21 in and out. This will permit the operator toselect to what mesh the material should be ground to.

The material is fed into the inlet hopper l6 and passes through theopening 29 in the casing portion 11 and opening 31 in member 26 flowingaround shaft 21 and enters the area at the entrance end of the grindingmembers 24 and 26 where it is distributed and gradually 'be fed betweengrinding members 24 and 26 by impellers 28, with the member 24 rotatingclockwise. It will be understood that the teeth 51 of the blades 39 areseparated further apart at the inner ends of blades 39 than at theirouter ends by reason of the slanted bottom walls 35 of the recesses 34,and furthermore, that the teeth 51 at such inner ends are relatively ofa coarse pitch, and the teeth at the outer ends are of a fine pitch, andare progressively graduated therebetween along the length of blades 39.In this way, it is ensured that even relatively coarse material canfreely enter between members 24 and 26 at their inlet ends, and as suchmaterial is progressively moved by the centrifugal movement of member 24in an outward manner, the material becomes more and more finely groundin a gradual progressive manner as the teeth 51 become closer and closertogether 7 and as their pitch (i.e. fineness) increases. In addition, itwill be noted that by reason of the arcuate shaping of blades 39, whicharcuate shaping is arranged on members 24 and 26 respectively to bedirected in an opposite direction, the inner ends of the blades 39 willpass one another in a more or less radial manner, the intermediateportions of blades 39 will pass over one another at intersecting angleswhich become progressively greater, towards the outer end of the blades39, and,at the outer ends of the blades 39, they will pass one anotherwhile alined in an almost circumferential manner. At each of theintersections, a progressively finer grinding action takes place in apredetermined manner and as a result the material is gradually broughtdown from a coarse grade to a time uniform mesh. Simultaneously with theaforesaid grinding action, a'certain degree of air is entrained in thechannels defined between adjacent blades 39, by reason of the impellingaction of the rotating impellers 28, and also by reason of thecentrifugal action of grinding member 24, and the passage of such airboth materially increases the efficiency of the grinding by causing aconstant outward flow of finely ground material which is entrained withsuch air, and also maintains an even temperature in the blades 39 andmembers 24 and 26, thereby avoiding any deterioration of the materialduring grinding. 7 A

In some cases, it may be desireable to provide a somewhat more gentlegrinding action, depending upon the particular type of material beingground. In this case, it is possible to obtain such a change by merelyreversing the direction of rotation' of the rotating grinding member 24.In this case, the grinding member 24 may be rotated anticlockwise sothat the outer ends of the blades 39 are directed in a trailing manner.In this case, the intersections of the blades 39 will obviously takeplace at the same place, but at the material to be ground is fed inbetween the members 24 and 26, the anticlockwise rotation of member 24causes the material to be ground to pass between blades 39 in adifferent manner, whereby a smoother grinding action take place.

It is found by experience, tl1at blades 39 will provide a very muchlonger life for effective grinding operation than the conventionalgrinding disk of the prior art in which the teeth are out directly intosolid metal in the disk In addition, when the teeth 51 of blades 39 dobecome blunt, all that is required is to remove the ring members 30,release the annular members 41 and remove the blade 39. New blades 39can then be inserted and annular members 41 replaced and the grindingmembers 24 and 26 are then ready for further use. In addition, it isapparent that such renewal of grinding members 24 and 26 can be done bytotally unskilled labourv all that is required, is a supply of newblades 39. This is to be distinguished from the practice in the priorart where the dressing of grinding stones was considered to be a veryhighly skilled task requiring many years of apprenticeship.

In addition to the foregoing, many other variations in the type ofgrinding effect produced can be obtained by varying the shape of blades39 and spacers 40. With reference to FIG. 7, this schematic illustrationshows one preferred form of calculating the required radius of are forthe blades 39 and spacers 40. In FIG. 7, R represents the outside radiusof the ring member 30 and radii r represents the inner radius thereof,such radii being measured with reference to the maximum width of therecess 34.

It will be understood that the length and radius of are, or othershaping, of saw blades 39 and spacers 40 may be varied in a number ofways. There are various factors which must be taken into considerationhowever. With reference to FIG. 7, it is quite clear that thecircumference of the circle R is very much greater than thecircumference of the circle r, and this is obviously a major factor tobe taken into consideration when considering the shaping and arrangementof the blades 39 and the spacers 40, since, depending upon how they aremade and arranged, they will tend to be spaced somewhat apart from oneanother at the circumference of R, notwithstanding the fact that theyare tightly packed together at the circumference r. FIG. 9, shows ingreatly exaggerated form the effect of this tendency, which is to becompared with FIG. 3, which shows the blades 39 and spacers 40 closelypacked together. A certain degree of spacing between the blades 39 andspacers 40 is considered desireable according to the practice of theinvention, at least towards their outer ends adjacent the circumferenceof the circle R, since this provides a spring action to the blades 39which is found to somewhat increase the efficiency of the grindingoperation. Preferably, the spacing between the blades 39 and spacers 40may be varied somewhere between one and five one-thousandths of an inchfor the grinding of wheat and the like, or although when grinding othermaterials, this may not necessarily be desireable. Obviously, such arelatively small spacing at the outer ends of blades 39 and spacers'40cannot be achieved if the blades and spacers aremade completelystraight, and in fact, the use of a substantial degree of curvature inthe blades 39 and spacers 40 is found to very much reduce the spacingbetween them at their outer ends, to somewhere within the acceptablerange. This effect is obviously maximized by arranging the blades 39 andspacers 40 around quite a substantial are, up to or of are, by means ofwhich the inner ends of the blades 39 and spacers 40 at thecircumference of the circle r lie in a more or less radial manner, andthe outer ends of the blades 39 and spacers 40 at the circle R lie in amore or less tangential manner relative to the circumference of thecircle R. In this way, the blades and spacers 39 and 40 occupy theminimum of space around the circumference of the circle r, and occupythe practical maximum of space around the circumference of the circle R.However, as stated above, it is not necessarily found to be desirable toachieve a perfect geometrical, arrangement of the blades 39 and spacers40 which would eliminate the spacing between their outer ends, someflexibility of movement being found to improve the grinding action asstated above. In addition, it is found that it is desirable to makeblades 39 and spacer 40 having different arcs for different grindingapplications. In fact, it is found to be desirable that the radius ofarc of the blades 39 and spacers 40 should, to a certain degree, followthe accepted teaching in the art of dressing grinding stones and disk(see for example a handbook entitled Malomipar Gyakorlati MuszakiSzakkonyv published by Malomujsag (Milling Magazine) Kiadasa, Budapest,V., Hollan-Utca 9, in November, 1942, from pages 96 through toThus,.according to such prior art teaching in relation to dressinggrinding disks one acceptable method calculating the radius of arc oftheblades 39 and spacers 40 is shown roughly in FIG. 7. According tothis method, the circles of radius R and r are drawn out as shown, andan additional circle of radius r/x is drawn, in this case equal tosomewhere about 0.75 percent, of R and, without changing this radius, aseries of arcs are drawn in, between the circles r and R, from centersspaced around the circle r/x. Obviously, by varying the fraction r/xvarious different blade shapes can be drawn in, the more pronouncedcurve in the blade being generally desirable for grinding of finermaterial, and the straighter blades being desirable for coarsermaterials.

In some cases, it may be desirable to use blades 39 which are spacedfurther apart, in which case spacer 40 can be used doubled up, or can bemade of thicker material, or, as shown .tachment ring in a generallyradial manner at their inner ends,

I and meet said outer attachment ring in a nonradial manner.

in FIG. 8, the blades 39 can be separated by specially shaped or mouldedspacers 40a, alternatively these spacers 40a can be formed of some formof thermo setting material such as babbitt metal or the like, as statedabove, In this case, it is possible to use an even wider variation inthe shaping of the blades 39 since obviously the use of such thermosetting material will accommodate any spacing, and any variation ofspacing between the circles r and R which may occur without any problem.

ln order to assist in the grinding of coarse material it may sometimesbe desirable to cut a series of crescent shaped grooves or indentationsby use of suitably shaped carborundum wheel, into the face formed by theblades 39 and spacers 40 much in the same manner as was formerlypractised in the art of dressing grinding stones and disks, suchindentations being omitted from the drawings for the sake of clarity.

in addition there may be added, if desired, a small band of circularblades (not shown) extending around the periphery of each of grindingmembers 24 and 26 to provide afurther fine grinding effect, althoughgenerally this is unnecessary.

The foregoing is a description of a preferred embodiment of theinvention only and is given here by way of example. The

invention is not to be taken as limited to any of the specific featuresdescribed, but comprehends all such variations thereof as come withinthe scope of the appended claims.

We claim:

l. A grinding disk for use in association with disk grinding apparatusof the type having a rotary grinding disk and a stationary grinding diskwherein the material to be grounded enters between the disks from acentral aperture extending through oneof the disks, and comprising:

a generally cirrular support member;

inner and outer attachment ring means on said support member;

annular supporting platform means extending between said inner and outerattachments means on said support member;

a plurality of separate blade members extending between said inner andouter attachment ring means and having grinding teeth formed on one edgethereof; and

spacer means between said blade members.

3. The apparatus as claimed in claim 1 wherein said support membercomprises an annular disk: having a central aperture therethrough, arecess formed in one side face of said disk and extending therearound inan annular manner and defining inner and outer wall means on either sideof said recess and a supporting floor extending therebetween, said innerand outer wall means. i i

4. The'apparatus as claimed in claim 1 wherein a portion at least of onesaid attachment ring; means is removable for removal and replacement ofsaid blade members.

5. The apparatus as claimed in claim 1 wherein said blade members haveinner and outer ends, and including teeth formed along one edge of saidblade means of varying size the teeth at the inner en thereof beingrelatively coarse, and the members and spacer means are held firmlytogether around said inner attachment ring means, and are spaced apartfrom one another towards said outer attachment ring means.

8. The apparatus as claimed in claim 1 wherein said blade members haveinner and outer ends, and including retaining tongue members extendingfrom said inner and outer ends for interengagement by and with saidinner and outer attachment ring means. i

a 9. The apparatus as claimed in claim 1 wherein said blade members andspacer means are arranged one beside the other,

alternatively around the entire extent of said support member.

10. The apparatus as claimed in claim 1 including additional blademembers arranged to form an annular band located and spaced outwardlyfrom said separate blade members and spacer means. i

1l.The apparatus as claimed in claim 1 wherein said blade members andspacer means are arranged with a plurality of said blade membersadjacent to one another in groups, each said group of blade membersbeing separated by spacer means.

12. The apparatus as claimed in claim 1 wherein said spacer meanscomprise sheet metal members out and shaped to conform to the shape ofsaid blade members and having inner and outer ends, and incorporatinginner and outer tongue means for interengagement by and with said innerand outer attachment ring means.

13. The apparatus as claimed in claim 1 wherein said spacer meanscomprises any suitable material having a plastic phase and a solidphase, said material being poured between said separate blade memberswhile in said plastic phase and allowed to set in said solid phase.

